Telescoping drill joint



July 13, 1965 Filed Sept. 24, 1962 c. WARE ETAL 3,194,330

TELESCOPING DRILL JOINT 2 Sheets-Sheet 1 Eff! ATTORNEY United States Patent 3,194,339 TELESCGPENG BRKLL lllllhlll Cecil Ware, William B. Charleville, and Franklin L.

be Bus, Six, Longview, Tern, assignors, by mesne assignments, to Bowen Tools, End, a corporation of Texas Filed Sept. 24, 1962, Ser. No. 225,556 iClaims. (El. 175-3231) This invention relates to improvements in well drilling apparatus and more particularly, but not by way of limitation, to a telescopic drill joint particularly designed and constructed for facilitating the drilling of a well bore from a floating barge, drilling platform, or the like.

There is much activity today in the petroleum industry in the drilling of off-shore well bores, and the like, for the recovery of petroleum products from deposits beneath lakes, or other water areas. It is comm-on practice to erect or position a drilling platform or barge in the vicinity of the petroleum deposit in order to provide a drilling site for the usual drilling operation. As a result, the drilling platforms are often disposed in the water, and are usually so arranged as to adjust to the vertical fluctuations of the water due to swells, and the like. Thus, the drilling platform substantially continually rises and falls during the drilling operation, and as a result, the drill string, which extends downwardly from the drilling platform and through the water, is moving up and down substantially continually during the drilling operation. This makes it very diificult to maintain a constant pressure on the drill bit and is a problem in this type of drilling operation.

The present invention contemplates a novel telescopic drill collar or joint adapted to be interposed in the drill string above the drill bit whereby vertical fluctuations of the drill string due to the movement of the drilling platform will not be transmitted to the drill bit. The telescopic action of the drill joint permits the upper portion of the drill string to reciprocate freely with the movement of the drilling barge and absorbs the vertical movement thereof for precluding translation of the motion to the lower portion of the drill string and the bit carried thereby. Thus, the bit is undisturbed by the fluctuations of the drilling platform, and the pressure on the drill bit may be maintained substantially constant throughout the drilling operation.

The novel drill joint is provided with inner and outer telescopic members having complementary male and female splines whereby the inner and outer sleeves may be locked in a telescopically collapsed position during lowering of the drill string. Subsequent to the lowering of the drill string in the 'well bore, the splined connection may be readily disengaged to release the locking engagement between the telescopic members and permit relative longitudinal movement therebetween. In this position, a drive connection is provided between the teleseopic members whereby rotation of the upper portion of the drill string is transmitted to the lower portion thereof and to the drill bit. This driving connection combined with the telescopic action of the drill joint provides for a continual drilling operation without transmitting vertical movement of the drilling barge to the drill bit. Any vertical fluctuations of the drilling platform which tend to raise and lower the upper portion of the drill string are absorbed by the telescopic action of ice the drill joint, and the lower portion of the drilling string, which carries the drill bit, is not affected thereby. In addition, sealing means is provided between the telescopic sleeves to preclude upward flow of the drilling fluid in the annular space between the telescopic members and assure circulation of the fluid through the central bore of the tool, and to the drill bit.

It is an important object of this invention to provide a novel drill joint adapted to be interposed in a drill string for facilitating the drilling of well bores in petroleum deposits located under water.

It is another object of this invention to provide a novel drill joint particularly designed and constructed for maintaining a substantially constant pressure on a drill bit during drilling operations performed from a floating drilling platform.

Another object or" this invention is to provide a novel telescopic drill joint wherein the telescopic action thereof absorbs vertical fluctuations of a floating drilling barge to preclude transmission of the fluctuations to the drill bit.

Another object of this invention is to provide a novel telescopic drill joint wherein elficient fluid circulation through the tool is assured for facilitating the drilling operation.

A further object of this invention is to provide a novel drill joint adapted to be interposed in a drill string whereby a combined driving connection and telescopic action is obtained between the upper and lower portions of the drill string in order to maintain a substantially constant pressure on the drill bit during a drilling operation.

A still further object of this invention is to provide a telescopic drill joint for facilitating drilling of a well bore from a floating drilling platform and wherein the telescopic members thereof may be locked in a collapsed engagement during lowering of the drill string into a well bore.

A still further object of this invention is to provide a novel telescopic drill joint for facilitating the drilling of subterranean well bores and which provides for the insertion of additional sections of drill pipe in the drill string without raising the drill bit at the bottom of the well bore.

It is a still further object of this invention to provide a novel telescopic drill joint for facilitating the drilling of a Well bore from a floating drilling platform and which is simple and eflicient in operation and economical and durable in construction.

Other and further objects and advantageous features of the present invention will hereinafter more fully appear in connection with a detailed description of the drawings in which:

FIGURE 1 is a broken elevational view partly in section of the upper portion of a telescopic drill joint embodying the invention and depicted in a telescopically collapsed position.

FIGURE 1A is a broken elevational view partly in section of the lower portion of a telescopic drill join-t embodying the invention and depicted in a telescopically collapsed position.

FIGURE 2 is a sectional View taken on line 22 of FIGURE 1.

FIGURE 3 is a sectional view taken on line 33 of FIGURE 1.

FIGURE 4 is a sectional view taken on line 4-4 of FIGURE 1A.

. string (not shown).

FIGURE 5 is a viewsimilar to FIGURE 1 depicting, the telescopic drill joint in an extended posi.tion.-

FIGURE 5A is a View similar to FIGURE lA'depicting the telescopic drill joint in an extended position.

Referring to the drawings in detail, referencecharacter generally indicates a telescopic drill joint comprising an upper sub member 12 having a threaded box por-- tion 14 adapted to engage the upper portion of a drill The sub member 12 is threadedly secured at 16 to an inner drive mandrel 18 which is telescopically disposed within an outer sleeve or drive body 20. A drive bushing 22 is threadedly connected at 24 to the upper end of the drive body 20. for a purpose as will be hereinafter set forth. The inner periphery 26 of the; drive bushing 22 is preferably of a substantially square cross-sectional configuration, but not limited thereto, and

the upper sub 12,v as clearly shown -in FIGURE 1, whereby theengagement between the lower end 28 of the sub 12 and the upper end 30 of the bushing 22 will limit the downward movement of the inner mandrel 183 with respect to the outer sleeve 20. V

The inner drive mandrel 18 is preferably of a sub-' stantially square outer cross sectional configurationcomplementary to the square configuration of the inner periphery 26 of the drive bushing 22. 'However, it is to be understood that theconfigurationof the two complementary drive members may be of substantially any suitableconfiguration, and is not limited to the square shape depicted herein. The upper portion 32 of the inner drive mandrel 18 is of a rounded outer cross sectionalconfiguration to permit rotation of the inner mandrel 18 with respect to" the drive bushing 22 (and the outer drive body 20 in the collapsed position of the tool or drill joint 10, as will be hereinafter set forth in detail. The inner periphery 26 of the drive bushing 22 may be lined with a suitable anti-friction bearing member (not shown), if desired, for facilitating the telescopic action of the drill joint 19.

The lower end 34 of the mandrel 18 is reduced to provide a circular neck portion and an annular shoulder 36, and is provided with a threaded portion 38 conterminous with the shoulder 36 for receiving a ring 4% having a suitable resilient piston or cup member 42 carried thereby. A follower ring 44 maybe threadedly secured below the packing carrying ring for retaining the ring and cup 42 in position. The outer periphery of the cup 42 continually bears against the inner periphery of the outer'drive body r 20 for precluding any upward flow of fluid in the annular space 46 between the inner mandrel 18 and the outer ma ndrel 2t). a

A spline body 48 is threadedly secured at 50 to the-re duced lower neck portion 34 of the inner drive body 18, and is provided with at least .two diametrically opposed outwardly extending substantially J-shaped spline members 52. vThe J-shaped spline members 52 are provided with diverging upwardly curving arcuate shoulders 54- and i 56 (FIGURE 1A) in communication with longitudinally extending passageways 58. The passageways 58 are open at both the top and bottom ends thereof, and are circurn-. ferentially spaced or interposed between each J-splin'e member 52. A second longitudinal passageway 60 is formed by each J-spline 52 and is spaced from the'respective passageway 58 to provide a pocket having thelower 1 end 62 thereof closed. The passageways 58' are in open communication with the respective passageway 60 through isof a size slightly smaller than theouter diameter of opposedsplines, as shown herein, are preferred. Q

A plurality of inwardly extendinglug membe'rs72 are provided on the;inner periphery ofthe outer sleeve 20 and are spaced upwardly fromthe lower end thereof. It is Y a preferable to provide a lug member 72 corresponding to each longitudinal passageway 58, and each of the lugs :7 2 is. disposed in substantial alignment with one of thes-flat sides e of the square shaped inne r'periphe r y of the drive bushing 22. ,In this manner, alignment between the passageways and the respective lugs 72' will facilitate alignment between the drive bushing 22 and the square portion of the inner;

mandrel 18 :during operation of the dr-ill joint 10."

The lowenend of the outer drive body. 20,.is threaded'at 74 to receive a'lower bushing 7 6, which'in turn isprovided with a pin connection 78 at its lower end for connection with the. lower portionof the; drill stringinotishown).

Thus, the upper sub'member v12 may be 'thr'eadedly con-- nected with. the: upper portion .ofthe drill string andthe lower bushing member 76 may be'threadedly secured to the lower portion" of thedrill string for interposition of the drill collaror joint 10 therein. In addition, the inner drive 1 body 18' and spline body 48 are provided with a central bore 80 extending therethrough to provide a fluid c-irculat'ion passageway through the drill collar a substantially horizontally extending passageway 64 formed by the termination of the upper end of the shorter Operation 7 When it is desired to drill a well bore, or thelik'e,'from' a floating bargev or drilling platform (not shown) ,'the drill collar 10 may b'e'interposed in the drill string (not shown) as hereinbefore set forth; During'the lowering, of the drill string through thewaterxand into the well bore, it is prefer-' able that the. drill joint 10 be telescopically collapsed and locked in this contracted position.' In orderto accomplish sub member 12. As. the inner body 18 is lowered within a the outer sleeve 20, the J-sPlines-Slwillgbe brought into contact with thelugs 72; The arcuateconfiguration of the shoulders 54 and, 56 will .facilitate'engagement. of the lugs 72 with the respective passageways '58, and the con t-inuedlowering of the inner sleeve '18 will cause the lugs;

72 to enter the: passageways 58. ;It,is to be noted, thatthe rounded portion v32 of the innermandrellS will beposi tioned within therdri've bushing 22 in'this lowered position of themandrel 18 with respect. tothe outer sleeve ,20 as shown in FIGURE 1, thus permitting rotation of the'inner body '18 with respect'to the outer body 26.. In addition;

the length of travel of the'inner body 18 withinthe outer the lugs from the J-splines during the locking operation.

Subsequent to the .loweringof th'e inner body, 18 within the outer body 201, the inner body 18 may be rotated in a clockwise direction, th s moVingftheJ-spline's 52With respect to the lugs 72 until thelongitudinalshoulders 68 are brought into engagement therewith as shown in FIGURE i In "this position, the inuer body "18 may be raised slightly within the outer body 20, and the pockets 6% will thus be moved into engagement :with the'lugs 72Q The drill joint 10 is now latched or locked in thetelescopically collapsed orcontracted position, and the drill string may belowered in the well bore in the usual manner. The

outer drive body; 29 and lower-portion-oft the drill string, carryingthe drill bit (not shown) .will'be suspended or arenas-o supported by the connection between the lugs '72 and the shoulder 62 provided at the bottom of the pocket so.

When the drill string is lowered to the desired position within the well bore, the upper portion of the drill string may be lowered slightly for moving the inner drive body 18 downwardly until the lower shoulder 28 of the sub 17% is brought into contact with the upper shoulder 3d of the driving bushing 22. This action lowers the l-splines 52 with respect to the lugs 72 for removing the lugs 72 from the pockets 6d. The upper portion of the drill string may then be rotated ina counterclockwise direction for rotation of the inner drive body 18 to position the passageways 53 in alignment with the lugs 72. This position is achieved when the lugs 72 are brought into engagement with the longer leg 7%? of the adjacent J-splines 52. A vertical upward movement of the upper port-ion of the drill string will then move the inner mandrel l8 upwardly within ti outer sleeve 20 and disengage the spline body td from connection with the lugs 72.

As ereinbefore set forth, the passageways on the body are in alignment with the respective flat suria 72 are in alignment with the fiat surfaces of the quare inner periphery 2d of the drive bushing 22. Thus, the complementary square configurations will be in substantial alignment and a continued upward movement of the drill string and inner mandrel 18 will move the square portion of the mandrel 18 into the square portion 26 of the drive bushing 22 to provide a drive connection therebetween, as shown in FIGURES 5 and 5A. In this position, rotation of the upper portion of. the drill string is transmitted to the lower portion of the drill string and drill bit through the drive connection between the inner drive body 18 and the drive bushing 22 and outer drive body 2h.

The drilling operation may then be continued in the usual manner, with rotation of the upper portion of the drill string being transmitted to the lower portion thereof and the drill bit carried thereby. In addition, the pressure on the bit may be maintained substantially constant since the weight on the bit willbe in accordance with the combined weight of the outer drive body 2% and the drill collars disposed therebelow. Since the lower portion of the drill string and the drill bit are not raised in the well bore, the weight on the bit remains constant at all times during the drilling operation.

When the drilling platform or barge fluctuates with changes in the water due to swells, and the like, the upper portion of the drill string is usually raised or lowered accordingly. It will be readily apparent that vertical reciprocation of the upper portion of the drill string will cause the inner mandrel 18 to move or reciprocate within the outer drive body 26. However, the length of the square portion of the inner drive mandrel 13 is sufficient to provide an extended length of drive connection with the drive bushing, and thus reciprocation of the inner mandrel 18 Within the outer mandrel 2!) will not interfere with the continued rotation of the lower portion of the drill string and drill bit carried thereby. it is to be noted that a complete separation of the inner mandrel 18 from the outer sleeve it upon an upward movement of the inner sleeve 18 will be precluded by the engagement between the ring 4t} and the lower end of the drive bushing 22. Furthermore, fluid circulation through the drill string and drill joint 19 is assured since the cup member 42 provides a sealing engagement between the inner and outer mandrels to precludeupward movement of the fluid in the annular space 46 therebetween.

In the event it is desired to insert additional sections of drill pipe in the drill string during the drilling operation, the telescopic drill joint it) may be utilized as a slip joint whereby the upper portion of the drill string may be raised without disturbing the lower portion thereof, or the drill bit. The telescopic action of the drill joint provides for extension of the drill joint withd out a complete separation thereof, thus facilitating the addition or" drill pipe to the drill string.

From the foregoing, it will be apparent that the present invention provides a novel telescopic drill collar particularly designed and constructed for facilitating the drilling of well bores, and the like, in under water locations. Fluctuations of the drilling platform due to water swells, or the like, are absorbed by the telescopic action of the novel drill joint whereby the lower portion of the drill string and the drill bit carried thereby will remain undisturbed during the drillirn operation. In this manner, the pressure or weight on the bit may be maintained substantially constant since the entire weight on the bit is determined by the combined weights of the outer drive body and the drill collars secured therebelow. In addition, the novel telescopic drill joint provides a slip joint for the drill string for facilitating the insertion of additional sections of drill pipe therein when it is necessary to increase the length of the drill string. The novel telescopic drill collar is simple and er'dcient in operation and economical and durable in construction.

Whereas, the present invention has been described in particular relation to the drawings hereto, it should be understood that other and further modifications, apart from those shown or suggested herein, may be made within the spirit and scope of this invention.

What is claimed is:

l. A telescopic drill joint comprising a pair of telescopically arranged drive bodies interposed in a drill string, means provided on one of said bodies to permit independent rotation thereof with respect to the other or" said drive bodies in a telescopically collapsed position therebetween, spline means cooperating between the drive bodies for lockin the bodies in a telescopically collapsed position, said spline means comprising lug means carried by one of said bodies and passageway means provided on the other of said bodies for receiving the lug means therein, said passageway means including an offset portion for receiving the lugs in the telescopically collapsed position of the drive bodies, said spline means responsive to rotational and vertical movement of one of said drive bodies with respect to the other of said drive bodies to release the locking engagement therebetween and permit free reciprocation of the said one drive body with respect to the other throughout an extended length of engagement between the two drive bodies, and means cooperating between the drive bodies to provide a drive connection there-between in combination with a reciprocal action of said one drive body in the released position of the spline means and throughout the said extended length of engagement whereby vertical movement of one drive body is independent of the other drive body.

2. A telescopic drill collar comprising a mandrel adapted to be secured to the upper portion of a drill string, a second mandrel telescopically arranged with respect to the first mandrel and adapted to be secured to the lower portion of a drill string, means cooperating between the mandrels' to provide a driving engagement therebetween for transmitting rotation from the upper portion of the drill string to the lower portion throughout an extended length of telescopic movement between the mandrels, means provided on at least one of said mandrels to permit independent rotation thereof in a telescopically contracted position between the said drels, a plurality of passageways provided on one of said mandrels and each passageway having at least one open end, each passageway being provided with an offset recess having one closed end, a plurality of lug members provided on the other of said mandrels and adapted to engage the closed end of the otfset recess in the telescopically contracted position between the mandrels to provide a locking engagement therebetween, said lugs being removed through the open ends of the passage- Ways upon vertical and rotational movement of one fof the mandrelsrto permit a free reciprocation of at least:

one of the mandrels'with respect to the other through an extended length of driving engagement therebetween, saidindepeudent reciprocal movement and drive connection cooperating to preclude transfer of vertical movement ofthe upper. portion of the drill string to the lower portion thereof; 7 H i V V, 3. A telescopic drill collar comprisingan inner mandreladapted to be secured to the upper portion of a drill string, an outer mandrel adapted to be secured to the lower portion of a drill string and telescopically arranged with r'espect to the inner mandrel, means cooperating,

between themandrels'to provide a driving engagement therebetween and comprising a drive bushingtcarried by the, outer mandrel and a drive portion provided on the inner mandrel for cooperation with'the drive bushing totransmit rotation from the upper portion of thedrill string to the lower portion thereof throughout an BX-f tended telescopic travel of one of the mandrels with respect to the other, means provided on the inner man- .drelto permit independent rotation thereof in a telescopically collapsed positiodbetween the mandrels, a plurality of lugs provided on the outer mandrel, a plurality of passageways provided on the inner mandrel and each havingone open end and an ofiset'portion having a closed end, the open endof each passageway being provided for receiving a lug therein upon a downward movement of the inner mandrel with respect 'to the outer Ward movement of the inner mandrel and disengageable from said passageways upon a reverse rotational movement and a subsequent upwardrmovement of the inner,

mandrel to permit free reciprocation of the inner mandrel with respect to the outer mandrel throughout the said extended telescopic travel, means limiting the clownward movement of the inner mandrel with respect to the outer mandrel, and means precluding a complete,

eparation of the inner and outer mandrels during the telescopic action therebetween;

4. A telescopic drill collar as set forth in claim 3 wherein fluid passageway means is provided throughout 1 the length of the drill collar,-and seal means interposed between the inner and outer mandrels for precluding upward flow of the fluid therebetween to assure an efficient circulation of fluid through the drill collar.

5. A telescopic drill joint comprising a first'rnandrel adapted to be secured to the upper portion of a drill string, a second mandrel telescopically arranged with re-t spect to the first mandrel and adapted to be secured to means'therein, said passageway means including anoifset portion for receivingthe lug means therein upon a the lower portion of the drill string, means provided on combined left handrotational and vertical dow nward movement of the first mandrel with respect to the second mandrel for locking the mandrels in a telescopically con- 1 tracted position and said lugs, being removed from the ofiset portion by a right hand rotational and vertical upwardmovement of the first mandrel with respect to the second mandrel for releasing the locking engagement drels for transmitting rotation from the upper portion of the drill string to the lower portion thereof in the released position'of the mandrels and throughout an ex-,

tended telescopic engagement therebetween, and said therebetween, drive means cooperating between the mandrive connection and telescopic; action cooperating to' preclude transfer of verticalliltretuations iof the upper portion of the drillstring to thelo'wer portion thereof,

6. A telescopic drill joint asiseti forthin,clainrS and having meanslforlimiting the. downward movementof one mandrel? with respect to the other, and means for precluding complete separation of. the-mandrels during the telescopic action 'thereoiifi 7. A telescopic drill joint s set forth'in claim 5 and:

having a fluid passageway extending longitudinallytherethrough, and sealingfmeans interposed betweenthe man s drels. for precluding upwardflowofifluid'jtherebetween for assuring an efiicie'nt' circulation'of fluid through the L drill joint.

8. A telescopic .drill tool comprising r nandrel means adapted'to besecured to the lower; p'ortion'ofi a1 drill string, Second 'mandrelqmeans telescopically ar is ranged withxrespect.*to fthe first mandrel means and adapted to be secured =10 the flipper portion -of 'adrill 7 string, spline means cooperating between -the:m andrels: and responsive tojverticalandqrotational movements of 'one of said mandrel meansiorylocking both .-m andr el means in a telescopically collapsed ;position,;-said spline v means comprising a plurality of: lug members carried by;

the first mandrelmeans, a plurality' of passagewaysprovidedon thBpSQCOIld mandrel, eachiof s'aid passageways having one open end for receiving a lug therein vand hav-- ing an offset portion zwith a closedend .for, receivingfa: lug member thereagainst in the locked position of thew mandrel means, said spline means responsive to reverse.

vertical and rotational movement ofithe Jsaidrsione" mandrel means for releasing the locking-engagement and permitting free reciprocation of the said ,one mandrel means, swith respect to the otherithroughoutian extended length' of engagement between the twojmandrels',rneans -coi operating between thefirst and vsecond mandrel -means to' provide a drive s connectiontherebetween inthe released position of the spline meansand throughout the said extended length of telescopic travel, means provided onrthe second mandrel, meansto permit independentro,

V tation thereof in the collapseditelescopic position between the mandrel means',,and' said reciprocation-actioniand driveconnection cooperating to preclude transmitting of drill tool.v

9. A telescopic dIllL'jOlDlZ; comprising an inner mandrel adapted to'be secured to the upperportion of a drill' string, an outer mandrel telescopically arranged with the} inner mandrel and adapted to be isecuredlto the lower portion of thedrillstring, a plurality oft-spaced lug'menn .bers provided on-"the inner. peripheryof the outer mandrel, a plurality of passageways Providedoh-the outer" periphery of theinne'r mandrel and each oflsaidpassage I ways having one end thereof open for receiving one of the :lugs therein and permitting; removal' of the lugs therefrom and having an offset portion provided with a 7 closed end, saidlugs being positioned within-the offset 7 7 portions upon vertical and rotational movement of the inner mandrel with respect" to a the :outerimandrl :for locking the mandrelsl in a telescopicallycontracted posi-Qi i tion and removed from the offset portionsgand passageways upon a reverse rotational and verticalmovern'ent of i the inner mandrelwith respect to the outer'mahdrlpro:

viding for a release of thelocking: engagementbetween the mandrels, means cooperating between the mandrels to provide-a driving connection therebetween'for transmitting rotation from the upper portion of the drillstr'ing to the lower portion thereof and comprising a drivebush fl ing provided on the outer mandrel and a drive portion provided on the inner mandrel and spaced above the passageways, said drive portion being of an extended length and having a configuration complementary with the drive bushing whereby rotation is transmitted from the inner mandrel to the outer mandrel through an extended length in the released position of the passageways and lugs for permitting vertical fluctuations of the inner mandrel with respect to the outer mandrel, and means precluding a complete disengagement of the inner mandrel from the outer mandrel.

10. A telescopic drill joint as set forth in claim 9 and including sealing means interposed between the inner ,te-geso References Cited by the Examiner UNITED STATES PATENTS 5/59 Le Bus 175-321 3/60 Le Bus 17532l XR 10 CHARLES E. OCONNELL, Primary Examiner.

BENJAMIN BENDETT, Examiner. 

1. A TELESCOPIC DRILL JOINT COMPRISING A PAIR OF TELESCOPICALLY ARRANGED DRIVE BODIES INTERPOSED IN A DRILL STRING, MEANS PROVIDED ON ONE OF SAID BODIES TO PERMIT INDEPENDENT ROTATION THEREOF WITH RESPECT TO THE OTHER OF SAID DRIVE BODIES IN A TELESCOPICALLY COLLAPSED POSITION THEREBETWEEN, SPLINE MEANS COOPERATING BETWEEN THE DRIVE BODIES FOR LOCKING THE BODIES IN A TELESCOPICALLY COLLASPED POSITION, SAID SPLINE MEANS COMPRISING LUG MEANS CARRIED BY ONE OF SAID BODIES AND PASSAGEWAY MEANS PROVIDED ON THE OTHER OF SAID BODIES FOR RECEIVING THE LUG MEANS THEREIN, SAID PASSAGEWAY MEANS INCLUDING AN OFFSET PORTION FOR RECEIVING THE LUGS IN THE TELESCOPICALLY COLLASPED POSITION OF THE DRIVE BODIES, SAID SPLINE MEANS RESPONSIVE TO ROTATIONAL AND VERTICAL MOVEMENT OF ONE OF SAID DRIVE BODIES WITH RESPECT TO THE OTHER OF SAID DRIVE BODIES TO RELEASE THE LOCKING ENGAGEMENT THEREBETWEEN AND PERMIT FREE RECIPROCATION OF THE SAID ONE DRIVE BODY WITH RESPECT TO THE OTHER THROUGHOUT AN EXTENDED LENGTH OF ENGAGEMENT BETWEEN THE TWO DRIVE BODIES, AND MEANS COOPERATING BETWEEN THE DRIVE BODIES TO PROVIDE A DRIVE CONNECTION THEREBETWEEN IN COMBINATION WITH A RECIPROCAL ACTION OF SAID ONE DRIVE BODY IN THE RELEASED POSITION OF THE SPLINE MEANS AND THROUGHOUT THE SAID EXTENDED LENGTH OF ENGAGEMENT WHEREBY VERTICAL MOVEMENT OF SAID DRIVE BODY IS INDEPENDENT OF THE OTHER DRIVE BODY. 